Device Comprising Dielectric Interlayer

ABSTRACT

A process for preparing a device and a device including a substrate; an interlayer disposed on the substrate, wherein the interlayer comprises a cured film formed from an interlayer composition, wherein the interlayer composition comprises: an epoxy compound; a polyvinyl phenol; a melamine resin; a solvent; an optional surfactant; and an optional catalyst; a source electrode and a drain electrode disposed on a surface of the interlayer; a semiconductor layer disposed on the interlayer, wherein the semiconductor layer is disposed into a gap between the source and drain electrode; a back channel interface comprising an interface between the semiconductor layer and the interlayer, wherein the interlayer serves as a back channel dielectric layer for the device; a dielectric layer disposed on the semiconductor layer; a gate electrode disposed on the dielectric layer. Also an interlayer composition and an organic thin film transistor comprising the interlayer composition.

BACKGROUND

The present invention is directed to an interlayer composition anddevices formed therefrom.

For printed electronics, various metal nanoparticle inks includingsilver inks are broadly used in electronic device integrations. Theprinted conductor inks are often used as electrodes for various devicessuch as diodes and transistors. Therefore, in addition to highconductivity, the conductor ink should ideally provide a suitableinterface for charge injection in device applications. Challenges oftenencountered include the ink wetting on the substrates which affectsprinting quality (printing line quality/resolution), uneven or notsmooth surface of the substrate which makes the printing impossible, theloss of the ink conductivity and poor ink adhesion to substrates.

Previously Xerox® Corporation developed silver nanoparticles and inkswhich can be solution processed by ink jet printing for variouselectronic device applications. Xerox® Corporation has invented ananosilver particle which is stabilized by an organoamine U.S. Pat. No.8,765,025, which is hereby incorporated by reference herein in itsentirety, describes a metal nanoparticle composition that includes anorganic-stabilized metal nanoparticle and a solvent in which the solventselected has the following Hansen solubility parameters: a dispersionparameter of about 16 MPa^(0.5), or more, and a sum of a polarityparameter and a hydrogen bonding parameter of about 8.0 MPa^(0.5) orless. U.S. Pat. No. 7,270,694, which is hereby incorporated by referenceherein in its entirety, describes a process for preparing stabilizedsilver nanoparticles comprising reacting a silver compound with areducing agent comprising a hydrazine compound by incrementally addingthe silver compound to a first mixture comprising the reducing agent, astabilizer comprising an organoamine, and a solvent.

U.S. patent application Ser. No. 13/866,704, which is herebyincorporated by reference herein in its entirety, describes stabilizedmetal-containing nanoparticles prepared by a first method comprisingreacting a silver compound with a reducing agent comprising a hydrazinecompound by incrementally adding the silver compound to a first mixturecomprising the reducing agent, a stabilizer comprising an organoamine,and a solvent. U.S. patent application Ser. No. 14/188,284, which ishereby incorporated by reference herein in its entirety, describesconductive inks having a high silver content for gravure andflexographic printing and methods for producing such conductive inks.

Xerox® Corporation has developed flexographic and gravure inks based onsilver nanoparticle technology. U.S. patent application Ser. No.14/594,746, which is hereby incorporated by reference herein in itsentirety, describes in the Abstract thereof a nanosilver ink compositionincluding silver nanoparticles; polystyrene; and an ink vehicle. Aprocess for preparing a nanosilver ink composition is describedcomprising combining silver nanoparticles; polystyrene; and an inkvehicle. A process for forming conductive features on a substrate usingflexographic and gravure printing processes is described comprisingproviding a nanosilver ink composition comprising silver nanoparticles;polystyrene; and an ink vehicle; depositing the nanosilver inkcomposition onto a substrate to form deposited features; and heating thedeposited features on the substrate to form conductive features on thesubstrate.

U.S. patent application Ser. No. 14/573,191, which is herebyincorporated by reference herein in its entirety, describes in theAbstract thereof a nanosilver ink composition including silvernanoparticles; a clay dispersion; and an ink vehicle. A process forforming conductive features on a substrate is described includingproviding a nanosilver ink composition comprising silver nanoparticles;a clay dispersion; and an ink vehicle; depositing the nanosilver inkcomposition onto a substrate to form deposited features; and heating thedeposited features on the substrate to form conductive features on thesubstrate. Inks have been successfully formulated in non-polar solventssuch as decalin and bicyclohexyl and successfully printed using inkjetprinting technologies.

U.S. patent application Ser. No. 14/981,419, which is herebyincorporated by reference herein in its entirety, describes in theAbstract thereof an interlayer composition including an epoxy resin; apolyvinyl phenol; a poly(melamine-co-formaldehyde) polymer; a solvent;an optional surfactant and an optional catalyst. A device including asubstrate; an interlayer disposed thereon; and conductive features;wherein the interlayer is formed from a composition comprising an epoxyresin; a polyvinyl phenol; a poly(melamine-co-formaldehyde) polymer; anoptional surfactant and an optional catalyst. A process for formingconductive features on a substrate including depositing an interlayeronto a substrate; thermally curing the interlayer; depositing aconductive composition onto the interlayer to form deposited features;and annealing the deposited features to form conductive features.

U.S. patent application Ser. No. 15/099,937, which is herebyincorporated by reference herein in its entirety, describes in theAbstract thereof a composition formed from ingredients comprising: anepoxy; a polyvinyl phenol; a cross-linking agent; an epoxy silane; and asolvent. A printable medium and other devices made from the compositionare also disclosed.

A thin-film transistor (TFT) is a special kind of field-effecttransistor made by depositing thin films of an active semiconductorlayer as well as the dielectric layer and metallic contacts over asupporting (but non-conducting) substrate. A common substrate is glass,because the primary application of TFTs is in liquid-crystal displays.This differs from the conventional transistor, where the semiconductormaterial typically is the substrate, such as a silicon wafer. Organicthin-film transistor (OTFT) technology involves the use of organicsemiconducting compounds in electronic components. A thin film is alayer of material ranging from fractions of a nanometer (monolayer) toseveral micrometers in thickness.

In order to provide a high performance printed organic thin filmtransistor (OTFT), a controllable line width with a minimal line-to-linespacing is required for the OTFT source and drain electrode printing. Inaddition, the electric properties, such as charge-trapping and emissionat the interface of the interlayer and a semiconductor, are ofimportance as they affect transistor performance.

Solution based all-additive printing processes enable low costfabrication of electronic devices on a large area flexible substrate.These printing processes offer several advantages including fastprototyping with on-demand custom device; patterning devices at lowtemperature, and applying to a broad range of applications forelectronic device manufacture.

Many of these printing processes use organic semiconductors. Organicthin-film transistors (OTFT) have low electron or hole mobility. Becauseof this low mobility, the desired device performance requires a largeratio of the thin-film transistor (TFT) channel width to channel length(W/L). In order to achieve a high transistor current during device onstate, it is desired to make the channel length, which is the dimensionof the gap between the source and drain electrodes, as small aspossible. Shown in FIG. 1 is a cross-sectional view of a top-gate OTFT10. The OTFT 10 includes a substrate 12 and thereupon an interlayer 14.Source electrode 16 and drain electrode 18 form a gap or channel 20therebetween. Semiconductor layer 22 is disposed between the gap 20.Gate dielectric layer 24 is disposed upon the semiconductor layer 22.Gate electrode 26 is disposed upon the gate dielectric layer 24. Avoltage applied to the gate electrode imposes an electric field 28 intothe semiconductor channel, which accumulates or depletes charge carriedin the channel. The back channel interface 30 is the interface betweenthe semiconductor layer 22 and the interlayer 14. Since thesemiconductor layer 22 is thin (typically 50 nanometers), the gatevoltage has a strong field effect at the back channel interface 30. Inan undesired situation, charges may be moved in and out from theinterlayer 14 to the semiconductor 22, causing poor device performancein terms of slow subthreshold slope and higher off-state leakagecurrent.

Solution processable conducting materials including silver nanoparticleinks play an important role in electronic device integrations. Silvernanoparticle inks can be easily dispersed in suitable solvents and usedto fabricate various conducting features in electronic devices such aselectrodes and electrical interconnectors by low-cost solutiondeposition and patterning techniques and especially by ink jet printingtechnologies.

The conductive features formed from metal nanoparticles such as silvernanoparticle inks on suitable substrates, including glasses and flexibleplastic substrates, must have sufficient adhesion and mechanicalrobustness characteristics to enable proper electronic devicefabrications and functions. However, one of the issues is that adhesionon certain substrates such as glasses and polyimide may not be adequatein some instances for robust device fabrications. The adhesion issue wastackled previously by addition of a small amount of polymeric materialsincluding polyvinyl butyral (PVB) resin in silver conducting inks as anadhesion promoter. This approach is suitable for some applications.However, a potential disadvantage of this method is that the electricalconductivity of printed conductive features from such inks could, insome instances, be decreased significantly. Therefore, it is necessaryto develop effective methods to improve adhesion and enable formation ofdevices with robust mechanical properties without sacrificing electricconductivity of metal nanoparticle inks used in electronic deviceapplications.

Currently available compositions and methods are suitable for theirintended purposes. However a need remains for improved electronic devicecompositions and methods. Further, a need remains for an improved methodfor providing sufficient adhesion and mechanical robustnesscharacteristics while also maintaining desired electrical conductivityof the printed conductive features. Further, a need remains for aninterlayer composition having the characteristics of film formingcapability, adequate film adhesion, in embodiments, adequate filmadhesion to glass substrates, ability to accept conductive ink, inembodiments silver ink, wherein a film formed from the interlayer allowsdesired adhesion of conductive ink to the film, non-polar solvent basedsilver ink wettability, and desired conductivity. In embodiments, whatis desired is an interlayer composition providing a combination of thesedesired characteristics; that is, an interlayer composition thatprovides all of the following characteristics: film forming ability,film adhesion to glass, ink adhesion to film, non-polar solvent basedink wettability, and desired conductivity. Further, a need remains for ahigh performance printed organic thin film transistor (OTFT) andimproved method for preparing same, providing a controllable line widthwith a minimal line-to-line spacing which is required for the OTFTsource and drain electrode printing. In addition, a need remains for animproved device and process providing electric properties, such ascharge-trapping and emission at the interface of the interlayer and asemiconductor. Further, a need remains to address the issue that organicthin-film transistors (OTFT) have low electron or hole mobility. Becauseof this low mobility, the desired device performance requires a largeratio of the thin-film transistor (TFT) channel width to channel length(W/L). In order to achieve a high transistor current during device onstate, a need remains for improved devices and processes to make thechannel length, which is the dimension of the gap between the source anddrain electrodes, as small as possible.

The appropriate components and process aspects of the each of theforegoing U.S. patents and patent Publications may be selected for thepresent disclosure in embodiments thereof. Further, throughout thisapplication, various publications, patents, and published patentapplications are referred to by an identifying citation. The disclosuresof the publications, patents, and published patent applicationsreferenced in this application are hereby incorporated by reference intothe present disclosure to more fully describe the state of the art towhich this invention pertains.

SUMMARY

Described is a device comprising a substrate; an interlayer disposed onthe substrate, wherein the interlayer comprises a cured film formed froman interlayer composition, wherein the interlayer composition comprises:an epoxy compound; a polyvinyl phenol; a melamine resin; a solvent; anoptional surfactant; and an optional catalyst; a source electrode and adrain electrode disposed on a surface of the interlayer; a semiconductorlayer disposed on the interlayer, wherein the semiconductor layer isdisposed into a gap between and over the source and drain electrode; aback channel interface comprising an interface between the semiconductorlayer and the interlayer, wherein the interlayer serves as a backchannel dielectric layer for the device; a gate dielectric layerdisposed on the semiconductor layer; and a gate electrode disposed onthe dielectric layer.

Also described is a process for preparing a device comprising providinga substrate; disposing an interlayer composition on to the substrate,wherein the interlayer composition comprises: an epoxy compound; apolyvinyl phenol; a melamine resin; a solvent; an optional surfactant;and an optional catalyst; treating the interlayer composition to form acured interlayer film; disposing a source electrode and a drainelectrode on a surface of the interlayer; disposing a semiconductorlayer on the interlayer, wherein the semiconductor layer is disposedinto a gap between and over the source and drain electrode; wherein theinterlayer serves as a back channel dielectric layer for the device andwherein the interlayer serves as a back channel interface comprising aninterface between the semiconductor layer and the interlayer; disposinga dielectric layer on the semiconductor layer; and disposing a gateelectrode on the dielectric layer.

Also described is an organic thin film transistor comprising asubstrate; an interlayer disposed on the substrate, wherein theinterlayer comprises a cured film formed from an interlayer composition,wherein the interlayer composition comprises: an epoxy compound; apolyvinyl phenol; a melamine resin; a solvent; an optional surfactant;and an optional catalyst; a source electrode and a drain electrodedisposed on a surface of the interlayer; a semiconductor layer disposedon the interlayer, wherein the semiconductor layer is disposed into agap between and over the source and drain electrode; a back channelinterface comprising an interface between the semiconductor layer andthe interlayer, wherein the interlayer serves as a back channeldielectric layer for the device; a dielectric layer disposed on thesemiconductor layer; a gate electrode disposed on the dielectric layer;wherein the thin film transistor has current on-off ratio of at leastabout 10⁻⁵.

Also described is an interlayer composition comprising an epoxycompound, wherein the epoxy compound is an aliphatic epoxy compound orepoxy polymer made therefrom, and wherein the aliphatic epoxy compoundis a compound of the formula

wherein X is a saturated or unsaturated, linear, branched or cyclicaliphatic group having 1 to 60 carbon atoms and at least one oxygenatom; wherein Y is selected from the group consisting of a glycidylgroup, an epoxy group, an oxyalkyl (—OR) group, and a hydroxyl group,wherein R is an alkyl; wherein R¹ is selected from the group consistingof hydrogen, alkyl, or OR², wherein R² is a C₁ to C₃ alkyl group or anepoxy group; wherein m is from about 1 to about 10; wherein n is fromabout 1 to about 20; and wherein q is from about 0 to about 10; apolyvinyl phenol; a melamine resin; a solvent; an optional surfactant;and an optional catalyst.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a top gate organic thin filmtransistor.

FIG. 2 illustrates a microscope image of printed Ag lines printed ontoan epoxy interlayer in accordance with the present embodiments.

FIG. 3A illustrates processing steps for preparing an organic thin filmtransistor with the interlayer dielectric as the back channel interfacematerial in accordance with the present embodiments.

FIG. 3B illustrates further processing steps for preparing an organicthin film transistor in accordance with the present embodiments.

FIG. 3C illustrates further processing steps for preparing an organicthin film transistor in accordance with the present embodiments.

FIG. 3D illustrates further processing steps for preparing an organicthin film transistor in accordance with the present embodiments.

FIG. 3E illustrates further processing steps for preparing an organicthin film transistor in accordance with the present embodiments.

FIG. 4 is a graph illustrating transistor transfer characteristics.

DETAILED DESCRIPTION

In embodiments, an organic thin film transistor device is providedcomprising an interlayer, which is a cured/cross-linked film formed froma mixture composition. The mixture composition comprises a specificepoxy composition. Unlike other commercially available epoxy coatingmaterials, the interlayer composition herein offers superior wettabilityfor deposition of electrodes with well-defined line width andline-to-line spacing, and significantly improved adhesion for ink jetprinted silver traces. In addition, the organic transistor device showslow off-state leakage current and good sub-threshold slope, indicatingthat the interlayer provides the desired property as the back channeldielectric.

In order to achieve a high transistor current during device on state, itis desired to make the channel length, which is the dimension of the gapbetween the source and drain electrodes, as small as possible. Inembodiments herein, this is a achieved by using a specific interlayercoating to control the conductive ink contact angle and wettability toform well defined conductive line width and line-to-line spacing. Inaddition to controlling the conductive ink wettability, the interlayerserves as the back channel dielectric material for OTFT.

In embodiments, a device is provided comprising a substrate; aninterlayer disposed on the substrate, wherein the interlayer comprises acured film formed from an interlayer composition, wherein the interlayercomposition comprises: an epoxy compound; a polyvinyl phenol; a melamineresin; a solvent; an optional surfactant; and an optional catalyst; asource electrode and a drain electrode disposed on a surface of theinterlayer; a semiconductor layer disposed on the interlayer, whereinthe semiconductor layer is disposed into a gap between and on the topsurface of the source and drain electrode; a back channel interfacecomprising an interface between the semiconductor layer and theinterlayer, wherein the interlayer serves as a back channel dielectriclayer for the device; a dielectric layer disposed on the semiconductorlayer; a gate electrode disposed on the dielectric layer. Inembodiments, the semiconductor layer is disposed into a gap between thesource and drain electrode and over at least a portion of the topsurface of each of the source and drain electrode.

An organic thin film transistor device is described comprising aspecific interlayer and a method for making the same. In embodiments,the interlayer comprises a cured/cross-linked film formed from a mixtureof epoxy and polyvinyl phenol polymer as well as melamine resin. Inembodiments, the interlayer composition comprises:

an epoxy compound;

a polyvinyl phenol;

a melamine resin; and

an optional catalyst.

In embodiments, the interlayer composition comprises an aliphatic epoxycompound of the following formula, or an epoxy polymer made therefrom:

where X can be a saturated or unsaturated, linear, branched or cyclicaliphatic group having 1 to 70 carbon atoms, such as 1 to 60, 1 to 30, 2to 20 or 2 to 10 carbon atoms, and at least one oxygen atom; Y can bedefined as a glycidyl group, epoxy group, oxyalkyl (—OR) group orhydroxyl group; R can be an alkyl, such as C₁ to C₆ alkyl; R¹ can be ahydrogen atom, an alkyl, such as C₁ to C₆ alkyl, or an —OR₂ group, whereR₂ can be a C₁ to C₃ alkyl or an epoxy group; m ranges from 1 to 10,such as 1 to 5; n ranges from 1 to 20, such as 1 to 5 and q ranges from0 to 10, such as 1 to 5. In one embodiment, m and q are both 1. Inanother embodiment, m, n and q are all 1. The at least one oxygen atomin the aliphatic group X can be included as any oxygen containing group,including, but not limited to, glycidyl groups, epoxy groups, ethergroups, carbonyl groups, carboxylic acid ester groups, hydroxyl groups,oxyalkyl (—OR) groups and combinations thereof.

In embodiments, X is of the formula

In embodiments, Y is an epoxy group of the formula:

In certain embodiments, X is a saturated or unsaturated, linear,branched or cyclic aliphatic group having 1 to 60 carbon atoms and atleast one oxygen atom; Y is selected from the group consisting of aglycidyl group, an epoxy group, an oxyalkyl (—OR) group, and a hydroxylgroup, wherein R is an alkyl; wherein R¹ is selected from the groupconsisting of hydrogen, alkyl, or OR², wherein R² is a C₁ to C₃ alkylgroup or an epoxy group; m is from about 1 to about 10; n is from about1 to about 20; and q is from about 0 to about 10.

In embodiments, the interlayer composition comprises an epoxy compoundof the following formula, or an epoxy polymer made therefrom:

wherein X comprises an aliphatic group having from at least 2 to about20 carbon atoms, wherein the aliphatic group can be a saturated orunsaturated, linear, branched or cyclic aliphatic group, and wherein Xis free of aromatic moieties, and wherein n is from about 1 to about 20;such as 1 to 5, wherein R₁ and R₂ are each independently selected fromthe group consisting of a hydrogen atom, an alkyl group, in embodimentsa C₁ to C₆ alkyl, an OR² group, wherein R² can be selected from thegroup consisting of a C₁ to C₃ alkyl group, a glycidyl group, and anepoxy group.

In certain embodiments, the epoxy comprises one or more of the followingaliphatic compounds or an epoxy polymer made therefrom, where thealiphatic compounds are selected from compounds of the formula:

1,4-Butanediyl diglycidyl ether of the formula

1,6-Hexanediol diglycidyl ether of the formula

1,4-Cyclohexanedimethanol diglycidyl ether of the formula

Neopentyl glycol diglycidyl ether of the formula

1,2,3-Propanetriol glycidyl ethers of the formula

Trimethylolpropane triglycidyl ether of the formula

epichlorohydrin polymer of the formula

Pentaerythritrol polyglycidyl ether of the formula

Poly(ethylene glycol) diglycidyl ether of the formula

wherein n is from 1 to 15, such as 1 to 10, or from 3 to 9, inembodiments, from 2 to 15; and

Poly(propylene glycol) diglycidyl ether of the formula

wherein n is from 1 to 15, such as 1 to 10, or from 3 to 9, or from 2 to15, in embodiments from 2 to 10.

More examples of suitable aliphatic glycidyl epoxy include C12-C14glycidyl ether, Ethylhexylgylcidylether, Polyglycerol-3-glycidyl ether,Cyclohexanedimethanol-diglycidyl ether, Glycerol-trigylcidyl ether,Penthaerythritol-polyglycidyl ether, 2-Ethyhexyl-glycidyl ether;Tris-(hydroxyl phenyl)-methane-based epoxy and cycloaliphatic epoxides.Commercially available epoxies include GNS SG-8008, GNS SG-8116 and thePOLYPDX™ family of glycidyl ethers, such as POLYPDX™ R3, POLYPDX™ R6,POLYPDX™ R7, POLYPDX™ R9, POLYPDX™ R11, POLYPDX™ R12, POLYPDX™ R14,POLYPDX™ R16, POLYPDX™ R17, POLYPDX™ R18, POLYPDX™ R19, POLYPDX™ R20 andPOLYPDX™ R24, all of which are available from DOW Chemical Company ofMidland, Mich.

Any suitable or desired polyvinyl phenol can be selected for thecompositions herein. In embodiments, the polyvinyl phenol is selectedfrom the group consisting of poly(4-vinylphenol),poly(vinylphenol)/poly(methyl acrylate), poly(vinylphenol)/poly(methylmethacrylate), poly(4-vinylphenol)/poly(vinyl methyl ketone), andcombinations thereof.

Any suitable or desired melamine resin can be selected for thecompositions herein. In embodiments, the melamine resin comprises apoly(melamine-co-formaldehyde) based polymer. In embodiments, themelamine resin is selected from the group consisting ofpoly(melamine-co-formaldehyde), methylatedpoly(melamine-co-formaldehyde), butylatedpoly(melamine-co-formaldehyde), isobutylatedpoly(melamine-co-formaldehyde), acrylatedpoly(melamine-co-formaldehyde), methylated/butylatedpoly(melamine-co-formaldehyde), and combinations thereof.

The epoxy composition for forming the interlayer film may furtherinclude a solvent. Any suitable or desired solvent can be selected forthe present interlayer compositions. In embodiments, the solvent isselected from the group consisting of propylene glycol methyl etheracetate, propylene glycol monomethyl ether acetate, toluene, methylisobutyl ketone, butylacetate, methoxypropylacetate, xylene,tripropyleneglycol monomethylether, dipropyleneglycol monomethylether,propoxylated neopentylglycoldiacrylate, and combinations thereof.

In embodiments, the solvent can be a non-polar organic solvent selectedfrom the group consisting of hydrocarbons such as alkanes, alkenes,alcohols having from about 7 to about 18 carbon atoms such as undecane,dodecane, tridecane, tetradecane, hexadecane, 1-undecanol, 2-undecanol,3-undecanol, 4-undecanol, 5-undecanol, 6-undecanol, 1-dodecanol,2-dodecanol, 3-dedecanol, 4-dedecanol, 5-dodecanol, 6-dodecanol,1-tridecanol, 2-tridecanol, 3-tridecanol, 4-tridecanol, 5-tridecanol,6-tridecanol, 7-tridecanol, 1-tetradecanol, 2-tetradecanol,3-tetradecanol, 4-tetradecanol, 5-tetradecanol, 6-tetradecanol,7-tetradecanol, and the like; alcohols such as terpineol (α-terpineol),β-terpineol, geraniol, cineol, cedral, linalool, 4-terpineol,3,7-dimethylocta-2,6-dien-1ol, 2-(2-propyl)-5-methyl-cyclohexane-1-ol;isoparaffinic hydrocarbons such as isodecane, isododecane; commerciallyavailable mixtures of isoparaffins such as Isopar™ E, Isopar™ G, Isopar™H, Isopar™ L, Isopar™ V, Isopar™ G, manufactured by Exxon ChemicalCompany; Shellsol® manufactured by Shell Chemical Company; Soltrol®manufactured by Chevron Phillips Chemical Company; Begasol® manufacturedby Mobil Petroleum Co., Inc.; IP Solvent 2835 manufactured by IdemitsuPetrochemical CO., Ltd; naphthenic oils; aromatic solvents such asbenzene, nitrobenzene, toluene, ortho-, meta-, and para-xylene, andmixtures thereof; 1,3,5-trimethylbenzene (mesitylene); 1,2-, 1,3-, and1,4-dichlorobenzene and mixtures thereof, trichlorobenzene;cyanobenzene; phenylcyclohexane and tetralin; aliphatic solvents such asisooctane, nonane, decane, dodecane; cyclic aliphatic solvents such asdicyclohexyl and decalin; and mixtures and combinations thereof.

In embodiments, two or more solvents can be used.

The solvent can be provided in the interlayer composition in anysuitable or desired amount. In embodiments, the solvent is present in anamount of from about 50 to about 90 percent, or from about 60 to about80 percent, or from about 70 to about 80 percent, by weight, based onthe total weight of the interlayer composition.

The epoxy composition for forming the interlayer film may furtherinclude a surfactant. Any suitable or desired surfactant can be selectedfor the present interlayer compositions. The surfactant may be used toimprove the film quality. In embodiments, the surfactant is selectedfrom the group consisting of a silicone modified polyacrylate, apolyester modified polydimethylsiloxane, a polyether modifiedpolydimethylsiloxane, a polyacrylate modified polydimethylsiloxane, apolyester polyether modified polydimethylsiloxane, a low molecularweight ethoxylated polydimethylsiloxane, polyether modifiedpolydimethylsiloxane, polyester modified polymethylalkylsiloxane,polyether modified polymethylalkylsiloxane, aralkyl modifiedpolymethylalkylsiloxane, polyether modified polymethylalkylsiloxane,polyether modified polydimethylsiloxane, and combinations thereof.

In embodiments, the surfactant is a solvent based siloxane. Inembodiments, the surfactant is a silicone modified polyacrylate. Inembodiments, the concentration of the surfactant can be from about 0.01weight percent to about 2 weight percent, or from about 0.1 weightpercent to about 1.5 weight percent, or from about 0.5 weight percent toabout 1 weight percent. The surfactant can be a polysiloxane copolymerthat includes a polyester modified polydimethylsiloxane, commerciallyavailable from BYK Chemical with the trade name of BYK® 310; a polyethermodified polydimethylsiloxane, commercially available from BYK Chemicalwith the trade name of BYK® 330; a polyacrylate modifiedpolydimethylsiloxane, commercially available from BYK Chemical with thetrade name of BYK®-SILCLEAN 3700 (about 25 weight percent inmethoxypropylacetate); or a polyester polyether modifiedpolydimethylsiloxane, commercially available from BYK Chemical with thetrade name of BYK® 375. The surfactant can be a low molecular weightethoxylated polydimethylsiloxane with the trade name Silsurf® A008available from Siltech Corporation. For further detail, see U.S. patentapplication Ser. No. 13/716,892, filed Dec. 17, 2012, of Liu et al.,which is hereby incorporated by reference herein in its entirety.

In embodiments, the surfactant is present and is selected from the groupconsisting of a polyester modified polydimethylsiloxane, a polyethermodified polydimethylsiloxane, a polyacrylate modifiedpolydimethylsiloxane, a polyester polyether modifiedpolydimethylsiloxane, a low molecular weight ethoxylatedpolydimethylsiloxane, and combinations thereof.

The surfactant can be provided in the interlayer composition in anysuitable or desired amount. In embodiments, the surfactant is present inan amount of from about 0.01 to about 2 percent, from about 0.1 to about1.5 percent, or from about 0.5 to about 1 percent, by weight, based onthe total weight of the interlayer composition.

The interlayer composition can optionally comprise a catalyst. Anysuitable or desired catalyst can be selected for the present interlayercompositions. In embodiments, the catalyst is selected from the groupconsisting of amine salts of dodecylbenzene sulfonic acid (DDBSA), paratoluene sulfonic acid, triflouromethane sulfonic acid, and combinationsthereof.

The catalyst can be provided in the interlayer composition in anysuitable or desired amount. In embodiments, the catalyst is present inan amount of from about 0.05 to about 1.5 percent, or from about 0.08 toabout 1.0 percent, or from about 0.1 to about 0.5 percent, by weight,based on the total weight of the interlayer composition.

A cured film can be prepared from the present interlayer composition.The cured film has very good uniformity with less than 50 nanometersroughness as measured by Profilometers manufactured by NANOVEA®. Inembodiments, the cured film thickness is from about 0.2 to about 5micrometers and possesses a water contact angle of from about 65 degreesto about 95 degrees.

The present disclosure also encompasses a method for preparing theinterlayer for transistor applications. In embodiments, a process forpreparing a device comprises providing a substrate; disposing aninterlayer composition on to the substrate, wherein the interlayercomposition comprises: an epoxy compound; a polyvinyl phenol; a melamineresin; a solvent; an optional surfactant; and an optional catalyst;treating the interlayer composition to form a cured interlayer film;disposing a source electrode and a drain electrode on a surface of theinterlayer; disposing a semiconductor layer on the interlayer, whereinthe semiconductor layer is disposed into a gap between and over thesource and drain electrode; wherein the interlayer serves as a backchannel dielectric layer for the device and wherein the interlayerserves as a back channel interface comprising an interface between thesemiconductor layer and the interlayer; disposing a gate dielectriclayer on the semiconductor layer; and disposing a gate electrode on thedielectric layer. FIG. 1 illustrates an example of disposing thesemiconductor layer into a gap between and over at least a portion ofthe source and drain electrode.

In embodiments, the method comprises:

providing an epoxy interlayer composition as described herein, inembodiments, comprising an epoxy compound of formula (I), a polyvinylphenol, a melamine resin, an optional catalyst, and a solvent;

disposing the epoxy interlayer composition onto a surface of antransistor; and

thermally curing the disposed interlayer composition layer to form acured interlayer film.

Further, a device containing the present epoxy interlayer compositioncan be prepared by any suitable or desired method. In embodiments, aprocess for forming conductive features on a substrate comprisesdepositing an interlayer composition as described herein onto asubstrate; curing the interlayer to form an interlayer film; depositinga conductive composition onto the interlayer film to form depositedfeatures; heating (or annealing) the deposited features to formconductive features.

Any suitable or desired material can be used to form the conductivefeatures. In embodiments, a metal nanoparticle ink composition isselected. Xerox Corporation has developed ink jet inks, flexographicinks, and gravure inks based on silver nanoparticle technology. Theseinks can be selected for embodiments herein. U. S. Patent Publication2014/0312284 (application Ser. No. 13/866,704, which is herebyincorporated by reference herein in its entirety, describes in theAbstract thereof a nanosilver ink composition including silvernanoparticles; a small amount of polymeric material (optional) and anink vehicle. A process for preparing a nanosilver ink composition isdescribed comprising combining silver nanoparticles, a small amount ofpolymeric material (optional) and an ink vehicle. A process for formingconductive features on a substrate using ink jet printing processes isdescribed comprising providing a nanosilver ink composition comprisingsilver nanoparticles; a small amount of polymeric material (optional)and an ink vehicle; depositing the nanosilver ink composition onto asubstrate to form deposited features; and heating the deposited featureson the substrate to form conductive features on the substrate.

U.S. Pat. No. 8,324,294, which is hereby incorporated by referenceherein in its entirety, describes in the Abstract thereof a nanosilverink composition including silver nanoparticles; a resin; and an inkvehicle. A process for forming conductive features on a substrate isdescribed including providing a nanosilver ink composition comprisingsilver nanoparticles, a resin and an ink vehicle; depositing thenanosilver ink composition onto a substrate to form deposited features;and heating the deposited features on the substrate to form conductivefeatures on the substrate. Inks have been successfully formulated innon-polar solvents such as decalin and bicyclohexyl and successfullyprinted using inkjet printing technologies.

The interlayer and any layer or layers including conductive layersdisposed thereon can be provided using any suitable or desired method.In embodiments, depositing the interlayer comprises solution depositingthe interlayer, and wherein, in embodiments, solution depositingcomprises a method selected from the group consisting of spin coating,dip coating, spray coating, slot die coating, flexographic printing,offset printing, screen printing, gravure printing, ink jet printing,and combinations thereof.

The depositing of the interlayer composition, and/or the optionally thenanoparticle ink composition or other layers provided on the device, maybe performed for example, by solution depositing. Solution depositing,for example, refers to a process where a liquid is deposited upon thesubstrate to form a coating or layer. This is in contrast to vacuumdepositing processes. The present processes are also different fromother solution-based processes, for example electroplating, whichrequires a plate to remain immersed in a solution and also requiresexposure to an electric current to form a metal coating on the plate.The present process also offers several advantages compared to otherprocess such as decreasing the amount of waste and decreasing the amountof time necessary to coat a substrate. Solution depositing includes, forexample, spin coating, dip coating, spray coating, slot die coating,flexographic printing, offset printing, screen printing, gravureprinting, or ink jet printing the interlayer composition onto thesubstrate.

In embodiments, disposing the interlayer composition comprises solutiondepositing the interlayer composition, and wherein the solutiondepositing comprises a method selected from the group consisting of spincoating, dip coating, spray coating, slot die coating, flexographicprinting, offset printing, screen printing, gravure printing, ink jetprinting, aerosol printing, and combinations thereof. In embodiments,disposing the interlayer composition comprises spin coating. In certainembodiments, disposing the interlayer composition comprises ink jetprinting, aerosol printing, or a combination thereof.

In embodiments, a hybrid process herein comprises wherein the layers areformed from a combination of solution processing techniques such as inkjet printing and conventional techniques such as spin coating, vacuumdeposition coating, and screen printing. In embodiments, a processherein comprises a hybrid process wherein the source and drainelectrodes, the semiconductor layer, and the gate electrodes aredisposed by ink jet printing; and wherein the interlayer composition anddielectric layer are disposed by conventional processes selected fromthe group consisting of spin coating, vacuum deposition coating, andscreen printing. In certain embodiments, a process herein comprises ahybrid process wherein the source and drain electrodes, thesemiconductor layer, and the gate electrodes are disposed by ink jetprinting; and wherein the interlayer composition and dielectric layerare disposed by processes selected from the group consisting of spincoating, vacuum deposition coating, screen printing, gravure printing,ink jet printing, aerosol printing, and combinations thereof.

The film formed from the interlayer composition can be coated at anysuitable or desired thickness. In embodiments, the dried film thicknessof the interlayer is from about 0.2 to about 5 micrometers, or fromabout 0.5 to about 3 micrometers, or from about 0.75 to about 1micrometers. In a specific embodiment, the coating thickness of theinterlayer is from about 0.2 to about 1 micrometer.

The device can possess, in embodiments, the properties of the interlayercomposition and film formed therefrom as described herein. Inembodiments, the device includes a thermally cured film prepared fromthe interlayer composition wherein the thermally cured film possesses awater contact angle of from about 65 degrees to about 95 degrees. Inembodiments, the thermally cured film possesses a surface roughness offrom about 1 nanometer to about 10 nanometers. In embodiments, thethermally cured film has a glass transition temperature of from aboutminus 10° C. to about 100° C. In embodiments, the thermally cured filmhas a thickness of from about 0.1 micron (micrometer) to about 5 microns(micrometers).

The film can be thermally cured at any suitable or desired temperature.In embodiments, thermal curing can comprise curing at a temperaturerange of from about 120° C. to about 160° C. for any suitable or desiredamount of time, in embodiments for from about 2 hours to about 6 hours.In embodiments, a cured film is provided by thermally curing theinterlayer composition described herein at a temperature of from about100° C. to about 200° C.

The device and process herein can comprise forming conductive featuresfrom a metal ink composition. In embodiments, the conductive compositioncomprises a metal nanoparticle ink composition. The fabrication ofconductive features, such as an electrically conductive element, from ametal ink composition, for example, from a nanoparticle metal ink, suchas a nanosilver ink composition, can be carried out by depositing thecomposition on a substrate using any suitable deposition techniqueincluding solution processing and flexographic and gravure printingprocesses at any suitable time prior to or subsequent to the formationof other optional layer or layers on the substrate. Thus deposition ofthe ink composition on the substrate can occur either on a substrate oron a substrate already containing layered material, for example, asubstrate having disposed thereon the present interlayer composition.

The substrate may be any suitable substrate including silicon, glassplate, plastic film, sheet, fabric, or synthetic paper. For structurallyflexible devices, plastic substrates such as polyester, polycarbonate,polyimide sheets, polyethylene terephthalate (PET) sheet, polyethylenenaphthalate (PEN) sheet, and the like, may be used. The thickness of thesubstrate can be any suitable thickness such as about 10 micrometers toover 10 millimeters with an exemplary thickness being from about 50micrometers to about 2 millimeters, especially for a flexible plasticsubstrate, and from about 0.4 to about 10 millimeters for a rigidsubstrate such as glass or silicon. In embodiments, the substrate isselected from the group consisting of silicon, glass plate, plasticfilm, sheet, fabric, paper, and combinations thereof.

In embodiments, a device herein can comprise a substrate, an interlayerdisposed thereover, and a conductive ink composition disposed over theinterlayer.

Heating the deposited conductive ink composition can be to any suitableor desire temperature, such as to from about 70° C. to about 200° C., orany temperature sufficient to induce the metal nanoparticles to “anneal”and thus form an electrically conductive layer which is suitable for useas an electrically conductive element in electronic devices. The heatingtemperature is one that does not cause adverse changes in the propertiesof previously deposited layers or the substrate. In embodiments, use oflow heating temperatures allows use of low cost plastic substrates whichhave an annealing temperature of below 140° C.

The heating can be for any suitable or desire time, such as from about0.01 second to about 10 hours. The heating can be performed in air, inan inert atmosphere, for example under nitrogen or argon, or in areducing atmosphere, for example, under nitrogen containing from about 1to about 20 percent by volume hydrogen. The heating can also beperformed under normal atmospheric pressure or at a reduced pressure of,for example, about 1000 mbars to about 0.01 mbars.

Heating encompasses any technique that can impart sufficient energy tothe heated material or substrate to (1) anneal the metal nanoparticlesand/or (2) remove the optional stabilizer from the metal nanoparticles.Examples of heating techniques include thermal heating (for example, ahot plate, an oven, and a burner), infra-red (“IR”) radiation, laserbeam, flash light, microwave radiation, or ultraviolet (“UV”) radiation,or a combination thereof.

In embodiments, after heating, the resulting electrically conductiveline has a thickness ranging from about 0.1 to about 20 micrometers, orfrom about 0.15 to about 10 micrometers. In certain embodiments, afterheating, the resulting electrically conductive line has a thickness offrom about 0.1 to about 2 micrometers.

The conductivity of the resulting metal element produced by heating thedeposited metal ink composition is, for example, more than about 100Siemens/centimeter (S/cm), more than about 1,000 S/cm, more than about2,000 S/cm, more than about 5,000 S/cm, more than about 10,000 S/cm, ormore than about 50,000 S/cm.

The resulting elements can be used for any suitable or desiredapplication, such as for electrodes, conductive pads, interconnects,conductive lines, conductive tracks, and the like, in electronic devicessuch as thin film transistors, organic light emitting diodes, RFID tags,photovoltaic, displays, printed antenna, and other electronic devisewhich required conductive elements or components.

In embodiments, a device herein comprises an organic thin filmtransistor comprising a substrate; an interlayer disposed on thesubstrate, wherein the interlayer comprises a cured film formed from aninterlayer composition, wherein the interlayer composition comprises: anepoxy compound; a polyvinyl phenol; a melamine resin; a solvent; anoptional surfactant; and an optional catalyst; a source electrode and adrain electrode disposed on a surface of the interlayer; a semiconductorlayer disposed on the interlayer, wherein the semiconductor layer isdisposed into a gap between and on a top surface of the source and drainelectrode; a back channel interface comprising an interface between thesemiconductor layer and the interlayer, wherein the interlayer serves asa back channel dielectric layer for the device; a dielectric layerdisposed on the semiconductor layer; a gate electrode disposed on thedielectric layer; wherein the thin film transistor has a current on-offratio of at least about 10⁻⁵.

In embodiments, a channel formed by the gap between the source and drainelectrodes has a large ratio of channel width to channel length.

In embodiments, the thin film transistor has a sub-threshold slope ofless than about 1 V/dec. In embodiments, the thin film transistor has asub-threshold slope of about 0.6 V/dec.

In embodiments, the interlayer herein provides a proper wettability forsilver inks to form well defined line width and line-to-line spacing. Inembodiments, the line spacing is less than about 35 μm. In embodiments,the interlayer provides a wettability sufficient to enable formation ofa silver ink line spacing of less than about 35 μm.

In embodiments, the interlayer cured film has a roughness of less than50 nanometers as measured by Profilometers manufactured by NANOVEA®.

In embodiments, the interlayer cured film has a thickness of from about0.2 to about 5 micrometers.

In embodiments, the interlayer cured film has a water contact angle offrom about 65 degrees to about 95 degrees.

EXAMPLES

The following Examples are being submitted to further define variousspecies of the present disclosure. These Examples are intended to beillustrative only and are not intended to limit the scope of the presentdisclosure. Also, parts and percentages are by weight unless otherwiseindicated.

Example 1

Interlayer compositions were prepared having the components provided inthe weight percentage of each component as described below.

Interlayer Components and Formulation.

10-50% by weight of Poly(propylene glycol) diglycidyl ether (PLGDE)Mn=380-2000; from Sigma-Aldrich.

5-20% by weight Poly(melamine-co-formaldehyde) methylated, solution fromSigma-Aldrich, average Mn˜432, 84 wt. % in 1-butanol.

5-30% by weight Poly(4-vinylphenol) (PVP powder); average Mw˜25,000.

20-80% by weight Propylene glycol methyl ether acetate (PGMEA)CAS#108-65-6 from Sigma-Aldrich.

Solution Preparation.

Step 1. A 10 to 30% poly(4-vinylphenol) (PVP) solution was prepared asfollows. 70 to 90 grams propylene glycol methyl ethyl acetate (PGMEA)solvent were charged into a glass bottle, followed by slowly adding 10to 30 grams PVP into the solvent with magnetic stirring at a speed ofabout 250 rpm/minute to around 500 rpm/minute. The stirring wascontinued for about one to two hours until the PVP was totally dissolvedin PGMEA solvent and the solution was clear.

Step 2. The interlayer composition components were then combined asfollows. The components were combined in a glass bottle in the amountsshown, as follows. The rest of the solvent was loaded into a glassbottle first, followed by the addition of the epoxy resin(Poly(propylene glycol) diglycidyl ether), the resin was totallydispersed in the solvent, followed by adding thePoly(melamine-co-formaldehyde) methylated, solution (PMMF) anddispersing the PMMF in the mixture before loading the PVP solution. Themixture was then roll-milled at 175 RPM for at least 2 hours.

Step 3. The interlayer solution was coated on different substrates suchas glass, polycarbonate (PC), polyethylene terephthalate (PET),polyethylene-naphthalate (PEN) film. The coating was cured at 120° C.for about 1-5 hours. The coated film thickness after cured is from 200nm to around 5 microns.

Example 2

Ink jet printing silver traces on the interlayer.

Samples were prepared by spin coating each of the interlayerformulations at 1600 RPM for 60 seconds, on polyethylene naphthalate(PEN) substrates. Subsequently, the samples were cured at 160° C. for 5hours in a vacuum oven.

Silver Nanoparticle Ink Composition.

A silver nanoparticle ink was prepared as described in U. S.

Patent Publication 2014/0312284 (application Ser. No. 13/866,704, whichis hereby incorporated by reference herein in its entirety.

The silver nanoparticle ink composition was prepared by mixing silvernanoparticle powders with a solvent mixture of bicyclohexane andphenylcyclohexane at a 3:2 ratio. The silver nanoparticles are 50 weightpercent of the silver formulation. After the silver nanoparticles weremixed into the solvents, the composition was filtered using a 1.0 μmsyringe filter. The composition was printed using a DMP-2800 ink jetprinter equipped with 10 pL cartridges. After printing and thermalannealing, the highly conductive features were formed.

Silver nano particle ink (from Colloidal, with 15% Ag loading) wasprinted onto the surface of the interlayer, with droplet spacing of 42millimeters.

FIG. 2 illustrates a microscope image of printed Ag lines. The linewidth and height are 50 nanometers and 300 nanometers respectively. Thegap between each electrode is about 30 millimeters. The printed tracesconducted well after sintering at 120° C. for 30 minutes.

FIGS. 3A-3E illustrate processing steps for preparing an organic thinfilm transistor 10 with the interlayer dielectric 14 serving as the backchannel interface material. The process starts with coating theinterlayer dielectric 14 over a substrate 12 as shown in FIG. 3A. Atypical coating condition is spin coating at 1600 RPM for 60 seconds.The layer is cured by thermal annealing at 160° C. for 5 hours. Next,the device source 16 and drain electrodes 18 are formed on the surfaceof the interlayer dielectric 14, such as by ink jetting silvernanoparticle ink, such as Colloidal ink with 15% silver loading. Gap 20exists between source 16 and drain 18 electrodes. Since the interlayerdielectric 14 has a proper wettability with the Ag ink, the printedtrace is well defined with about 30 millimeter spacing between thesource 16 and drain 18 electrode as shown in FIG. 3B. After sintering at120° C. for 30 minutes, the printed ink is electrically conductive.Next, p-type semiconductor ink such as FlexInk12 from FlexInk is printedonto the gap 20 between the source and drain electrodes to formsemiconductor layer 22. The printing was performed at a substratetemperature of 60° C. See FIG. 3C. After a brief anneal at 120° C. for10 minutes, a stack of gate dielectric layers 24 were spin coated overthe printed semiconductor along with the rest of the elements on thesubstrate as shown in FIG. 3D. The gate dielectric layer 24 includes 50nanometer Teflon™, 900 nm PVDF-TrFE-CTFE relaxor polymer. Each layer isthermally cured at 120° C. before coating the next layer. Next, a gateelectrode 26 is formed by ink jetting silver nano particle ink andsintering. See FIG. 3E. To contact the source and drain electrode, alaser drill through the gate dielectric stack was applied and followedby printing Ag pads connecting to the source and drain electrodesthrough the bias (not shown).

FIG. 4 shows the OTFT transfer characteristics, which has low off-stateleakage current and good sub-threshold slope. The low off-state currentresults in a high current on-off ratio. This performance indicates thatthe interlayer provides the desired property as the back channeldielectric.

Thus, in embodiments, an interlayer coating herein provides at least twodistinctive features for printed OTFTs:

1. a proper wettability for Ag inks to form well defined line width andline-to-line spacing;

2. service as the back channel dielectric layer for the transistor. Withthese features, the performance of OTFTs is dramatically improved.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also thatvarious presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims. Unless specifically recited in aclaim, steps or components of claims should not be implied or importedfrom the specification or any other claims as to any particular order,number, position, size, shape, angle, color, or material.

1. A device comprising: a substrate; an interlayer disposed on thesubstrate, wherein the interlayer comprises a cured film formed from aninterlayer composition, wherein the interlayer composition comprises: anepoxy compound; a polyvinyl phenol; a melamine resin; a solvent; anoptional surfactant; and an optional catalyst; a source electrode and adrain electrode disposed on a surface of the interlayer; a semiconductorlayer disposed on the interlayer, wherein the semiconductor layer isdisposed into a gap between and over the source and drain electrode; aback channel interface comprising an interface between the semiconductorlayer and the interlayer, wherein the interlayer serves as a backchannel dielectric layer for the device; a gate dielectric layerdisposed on the semiconductor layer; a gate electrode disposed on thedielectric layer.
 2. The device of claim 1, wherein the substrate isselected from the group consisting of silicon, glass plate, plasticfilm, sheet, fabric, and synthetic paper.
 3. The device of claim 1,wherein the substrate is selected from the group consisting ofpolyester, polycarbonate, polyimide sheets, polyethylene terephthalatesheet, and polyethylene naphthalate sheet.
 4. The device of claim 1,wherein the epoxy compound of the interlayer composition is an aliphaticepoxy compound or epoxy polymer made therefrom, wherein the aliphaticepoxy compound is a compound of the formula

wherein X is a saturated or unsaturated, linear, branched or cyclicaliphatic group having 1 to 60 carbon atoms and at least one oxygenatom; wherein Y is selected from the group consisting of a glycidylgroup, an epoxy group, an oxyalkyl (—OR) group, and a hydroxyl group,wherein R is an alkyl; wherein R¹ is selected from the group consistingof hydrogen, alkyl, or OR², wherein R² is a C₁ to C₃ alkyl group or anepoxy group; wherein m is from about 1 to about 10; wherein n is fromabout 1 to about 20; and wherein q is from about 0 to about
 10. 5. Thedevice of claim 1, wherein the epoxy compound of the interlayercomposition is selected from the group consisting of 1,4-butanediyldiglycidyl ether of the formula

1,6-hexanediol diglycidyl ether of the formula

1,4-cyclohexanedimethanol diglycidyl ether of the formula

neopentyl glycol diglycidyl ether of the formula

1,2,3-pPropanetriol glycidyl ethers of the formula

trimethylolpropane triglycidyl ether of the formula

epichlorohydrin polymer of the formula

pentaerythritrol polyglycidyl ether of the formula

poly(ethylene glycol) diglycidyl ether of the formula

wherein n is from 2 to 15; and poly(propylene glycol) diglycidyl etherof the formula

wherein n is from 2 to
 10. 6. The device of claim 1, wherein thepolyvinyl phenol is selected from the group consisting ofpoly(4-vinylphenol), poly(vinylphenol)/poly(methyl acrylate),poly(vinylphenol)/poly(methyl methacrylate),poly(4-vinylphenol)/poly(vinyl methyl ketone), and combinations thereof.7. The device of claim 1, wherein the melamine resin is selected fromthe group consisting of poly(melamine-co-formaldehyde), methylatedpoly(melamine-co-formaldehyde), butylatedpoly(melamine-co-formaldehyde), isobutylatedpoly(melamine-co-formaldehyde), acrylatedpoly(melamine-co-formaldehyde), methylated/butylatedpoly(melamine-co-formaldehyde), and combinations thereof.
 8. The deviceof claim 1, wherein the melamine resin comprises apoly(melamine-co-formaldehyde) based polymer.
 9. The device of claim 1,wherein the cured film is formed by thermally curing the interlayercomposition at a temperature of from about 100° C. to about 200° C. 10.The device of claim 1, wherein the solvent is selected from the groupconsisting of propylene glycol methyl ether acetate, toluene, methylisobutyl ketone, butylacetate, methoxypropylacetate, xylene,tripropyleneglycol monomethylether, dipropyleneglycol monomethylether,propoxylated neopentylglycoldiacrylate, and combinations thereof. 11.The device of claim 1, wherein the interlayer cured film has a thicknessof from about 0.2 to about 5 micrometers.
 12. The device of claim 1,wherein the interlayer cured film has a water contact angle of fromabout 65 degrees to about 95 degrees.
 13. The device of claim 1: whereinthe device is an organic thin film transistor, wherein the thin filmtransistor has a current on-off ratio of at least about 10⁻⁵.
 14. Thedevice of claim 1: wherein the device is an organic thin filmtransistor, wherein the thin film transistor has a sub-threshold slopeof less than about 1 V/dec.
 15. A process for preparing a devicecomprising: providing a substrate; disposing an interlayer compositionon to the substrate, wherein the interlayer composition comprises: anepoxy compound; a polyvinyl phenol; a melamine resin; a solvent; anoptional surfactant; and an optional catalyst; treating the interlayercomposition to form a cured interlayer film; disposing a sourceelectrode and a drain electrode on a surface of the interlayer;disposing a semiconductor layer disposed on the interlayer, wherein thesemiconductor layer is disposed into a gap between the source and drainelectrode; wherein the interlayer serves as a back channel dielectriclayer for the device and wherein the interlayer serves as a back channelinterface comprising an interface between the semiconductor layer andthe interlayer; disposing a dielectric layer on the semiconductor layer;and disposing a gate electrode on the dielectric layer.
 16. The processof claim 15, wherein treating the interlayer composition comprisesthermally curing the interlayer composition at a temperature of fromabout 100° C. to about 200° C.
 17. The process of claim 15, whereindisposing the interlayer composition comprises solution depositing theinterlayer composition, and wherein the solution depositing comprises amethod selected from the group consisting of spin coating, dip coating,spray coating, slot die coating, flexographic printing, offset printing,screen printing, gravure printing, ink jet printing, aerosol printing,and combinations thereof.
 18. The process of claim 15, wherein disposingthe interlayer composition comprises ink jet printing, aerosol printing,or a combination thereof.
 19. The process of claim 15, furthercomprising a hybrid process wherein the source and drain electrodes, thesemiconductor layer, and the gate electrodes are disposed by ink jetprinting; and wherein the interlayer composition and dielectric layerare disposed by processes selected from the group consisting of spincoating, vacuum deposition coating, screen printing, gravure printing,ink jet printing, aerosol printing, and combinations thereof.
 20. Aninterlayer composition comprising: an epoxy compound, wherein the epoxycompound is an aliphatic epoxy compound or epoxy polymer made therefrom,and wherein the aliphatic epoxy compound is a compound of the formula

wherein X is a saturated or unsaturated, linear, branched or cyclicaliphatic group having 1 to 60 carbon atoms and at least one oxygenatom; wherein Y is selected from the group consisting of a glycidylgroup, an epoxy group, an oxyalkyl (—OR) group, and a hydroxyl group,wherein R is an alkyl; wherein R¹ is selected from the group consistingof hydrogen, alkyl, or OR², wherein R² is a C₁ to C₃ alkyl group or anepoxy group; wherein m is from about 1 to about 10; wherein n is fromabout 1 to about 20; and wherein q is from about 0 to about 10; apolyvinyl phenol; a melamine resin; a solvent; an optional surfactant;and an optional catalyst.